Multiple First Order Transitions in Cr Thin Films

27th International Conference on Low Temperature Physics

Rodriguez, R.H.^1 ; Tosi, L.^1 ; Menghini, M.^2 ; Pastoriza, H.^1 ; Balseiro, C.A.^1

Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, CONICET, Bariloche

8400, Argentina^1

Department of Physics and Astronomy, KU Leuven, Leuven, Belgium^2

关键词: Film surfaces;    Hysteretic behavior;    Multiple first-order;    Multiple transitions;    Temperature decrease;    Temperature dependent;    Transport measurements;    Wave vector;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/568/4/042031/pdf
DOI  :  10.1088/1742-6596/568/4/042031

来源: IOP

【 摘 要 】

The incommensurate spin density wave (SDW) in metalic Cr forms below TN311K and is characterized by a temperature dependent wave-vector Q along thedirection. The wavelength varies from 78 Å at 300 K to 60 Å at 150 K. In thin films, the Q-vector orients perpendicular to the film surface and the SDW is forced to satisfy boundary conditions. As a consequence of the confinement, the SDW wavelength is quantized in a set of available modes, each one having n nodes. As the temperature decreases the wavelength does not follow a continuous bulk-type variation but jumps between different allowed values. These jumps occur at certain determined temperatures Tnas first order type transitions which are accompanied with a decrease (n to n + 1 nodes) or an increase (n + 1 to n nodes) of the resistance. In this work, we present transport measurements on Cr thin films showing hysteretic behavior in the resistance as a function of temperature in cooling-warming cycles. The hysteresis loops are thickness dependent and present structures which we associate with the possible multiple transitions that may occur as temperature is swept.